BMW is putting more space between its flagship crossover and the rest of its expanding crossover lineup.

The redesigned X5 crossover, coming in the fourth quarter, is slightly longer than the current model, gets a new front end and will be available with several new safety and communications features.

And for the first time, BMW will offer an optional rear-wheel-drive variant -- the sDrive35i -- in addition to all-wheel drive. The rwd model will be powered by BMW's 3.0-liter twin-turbo inline six-cylinder engine, which delivers 300 hp.

BMW expects most rwd vehicles to sell in Southern California, Texas and Florida.

BMW has released details and the first photos of the X5, which is expected to debut at the Frankfurt auto show in September. The automaker wants to further separate the X5 from the smaller X3.

The all-wheel-drive xDrive50i will continue to be offered with a 4.4-liter twin-turbo V-8 that puts out 445 hp. In early 2014, BMW will launch the X5 xDrive35d diesel with a new 255-hp 3.0-liter inline six-cylinder engine.

All of the engines will be teamed with a new eight-speed automatic transmission.

BMW has not disclosed pricing for the 2014 X5 models.

The X5 retains its upright profile and traditional features, such as a two-piece tailgate. There's a bolder front end with a more prominent kidney grille, LED headlamps and a heavily contoured bumper with so-called air-curtain ducts on the lower outer edges sending air more efficiently through the front wheel houses. The hood is more contoured and the shoulder line more pronounced.

The crossover has been lengthened by 1.3 inches to 192.4 inches, and height is increased by 0.6 inches to 69.4 inches. Width remains the same at 76 inches. The 115.5-inch wheelbase is the same.

BMW Apps, which will become standard, gives access to Internet radio and social media services.

BMW Apps, which is standard on the new X5, connects with an Apple iPhone, allowing access to social media, Internet radio services such as Pandora, and various other entertainment and information services.

Another optional feature is an active cruise control system that maintains a safe distance from the vehicle in front through use of a front camera and radar sensors. It will brake automatically if the driver does not react to warning of an imminent front crash. BMW builds the X5 in Spartanburg, S.C.

Greg Kable contributed to this report

The restyled front end of BMW's X5
has a more prominent kidney-shaped grille.